This application claims the priority benefit of Taiwan application serial no. 89103947, filed Mar. 6, 2000.
1. Field of Invention
The present invention relates to a method of operating a scanner. More particularly, the present invention relates to a multiple non-directional document scanning.
2. Description of Related Art
Due to rapid advance in computer technologies and multimedia systems, personal computers has become indispensable in our daily life. Other peripheral components related to our computer system are also developed simultaneously. For example, progress in image-processing techniques has lead to innovative image processors and scanners. In just a few years time, black-and-white palm-top type of scanners has become obsolete and replaced by full-color high-resolution type. Hence, the scanned image is more precise and real.
FIG. 1 is a perspective view of a conventional scanner. The scanner has a covering flap 10 and an external housing. The external housing can be further divided into a top casing 20 and a bottom casing 30. The top casing 20 includes a transparent glass panel 40. Scan document is placed between the covering flap 10 and the top casing 20. To scan a document, an image of the document passes through the transparent glass panel 40 to be picked up by a chassis. The chassis has optical sensor mounted thereon for receiving optical signals and transforming the optical signals into electrical signals of the image.
FIG. 2A is a sketch showing the top casing of a conventional scanner. Inside the top casing 20, there is a calibration ruler 60. The calibration ruler 60 is a reference for performing optical black and white chart calibration before an actual scanning using the chassis. The results from the calibration can be used to group various colors on a scan document. FIG. 2B is a sketch of the calibration ruler. The calibration ruler 60 has two colored regions, namely, the optical black region 64 and the white chart 62.
FIG. 3 is a flow chart showing the steps in operating a conventional scanner. As soon as a scan document is placed inside the scanner and the scan button triggered, the scanner first performs a calibration (in step 70). Scan parameters are next set (in step 80). Thereafter, the chassis is moved to the beginning of a document and started scanning so that ultimately a full image of the document is obtained (in step 90). After the completion of the scanning operation, the chassis has moved to the other side of the scanner. Hence, the driving motor must reverse direction of rotation so that the chassis is returned to the original position where the calibration ruler is located. This is the home-park operation (step 100). Once the chassis has returned to the home-park position, another document-scanning operation can be triggered.
Each document has to cycle through the calibration step 70, parameter setting step 80, image scanning step 90 and parking step 100. Hence, a lot of time is wasted in non-scanning preparations, lengthening the entire process of scanning multiple documents or a batch of documents.
Accordingly, one object of the present invention is to provide a multiple document non-directional scanning method that utilizes a program whose parameters are set according to user. The program controls the scanning direction so that optimal scanning can be conducted in both the forward and the backward directions. Hence, scanning operations such as batch scanning, preview and scanning can be completed in one cycle and a low-resolution forward/backward scanning can be used to obtain a high-resolution full-color image. Moreover, this invention eliminates the need for a home-park operation at the end of each document scanning so that the next round of scanning can start immediately. Therefore, a greater number of images can be captured within a given time.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a multiple non-directional scanning method. First, a document preview scanning is carried out from one end of the document to the other. The preview image is next analyzed to provide a set of scan parameters. After setting the scan parameters, the scanner performs a backward scanning operation from the other end of the document back to the original start-up position to obtain a final scan image.
This invention also provides a second multiple non-directional scanning method. First, the image of a first portion of a document is obtained as the chassis moves forward. Thereafter, the image of a second portion of the document is obtained as the chassis moves backward. Note that the image captured from the second portion of the document has no overlapping with the image captured from the first portion of the document image. Ultimately, the first and the second image are combined to form a final scan image.
This invention also provides a third multiple non-directional scanning method suitable for the scanning of a portion of each document consecutively. First, the image of a portion of a document is scanned. Thereafter, the scanner checks if there is any more scanning operation. If there is some more scanning to perform, the scanner decides if the next partial scanning of document is in the forward or the backward direction.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.